Integrated circuits are fabricated on the surface of a semiconductor wafer in layers, and later singulated into individual semiconductor devices, or “dies.” Many fabrication processes are repeated numerous times, constructing layer after layer until fabrication is complete. Metal layers, which typically increase in number as device complexity increases, include patterns of conductive material that are vertically insulated from one another by alternating layers of insulating material. Conductive traces are also separated within each layer by an insulating, or dielectric, material. Vertical, conductive tunnels called “vias” typically pass through insulating layers to form conductive pathways between adjacent conductive patterns. Defects in semiconductor devices may result from, among other things, diffusion of mobile species and deficiencies in the layers of materials forming device structures.
Metals are commonly employed in fabrication of semiconductor devices. Certain metals, e.g., cobalt, nickel, titanium, and platinum, may be suitable for employment as a constituent in formation of a metal silicide (or “silicide”), which may act as a low resistance contact between metal layers and the silicon substrate in a device. The processes involved in preparing a die for pre-silicide metal deposition and silicide formation may affect silicide film integrity, and the potential for undesirable diffusion of metal in the device.